QoS-Based Path Switching Mechanism in Mobile SCTP

In mobile SCTP, a mobile terminal has two or more network interfaces and vertical handover occurs when it moves from one network to another. The delay due to the handover process and the slow-start phase of SCTP's congestion control after handover cause substantial performance degradation. If the mobile node goes back and forth frequently, excessive handovers occur and data transmission quality deteriorates. In order to provide the required level of QoS for on-going application, the frequency of handovers should be kept minimized. In this paper, we propose a transport layer handover mechanism using the mobile SCTP. We take the QoS requirements of application as the major criterion in deciding path switching. In our mechanism, the mobile node in overlapping area does not perform handover if the current network metrics satisfy the QoS requirements of on-going application. Both analytic evaluation and simulation results show that the proposed mechanism significantly improves the throughput by suppressing unnecessary handovers. Our research results can also be applied to distributed mobile sensor networks.